This invention relates to an infrared radiation detector device including an array of detector elements comprising an array of interconnected electrodes for exposure to the infrared radiation to be detected, an array of discrete electrodes each connected to signal processing means, and pyroelectric material disposed between the arrays. The invention also relates to a method of manufacturing such a detector.
In such a device, the infrared absorption qualities required of the interconnected electrodes leads to a high sheet resistance (e.g. 377 .OMEGA. per square for a layer 15 nm thick). Furthermore it is desirable that the electrodes are thermally isolated from each other which further adds to the electrical resistance.
These requirements conflict with a requirement for adequate electrical conduction between the electrodes and leadout connections at the edges of the array, and also with the desirability of low electrical resistance between the electrodes to limit electrical noise and cross-talk.
EP-A-454398 discloses such a device including a network of further electrodes interspersed between the detector elements of the array. The electrodes are carried by support members disposed in gaps between adjacent elements. It is advantageous that the fill factor of the elements be as high as possible; that is, that the elements of the array each be as large as possible in relation to the gaps therebetween.